Alkyl and aralkyl resorcinol carboxylic acids



' Patented'Jan. l, 1929.

UNITED STAT-ES HANS STENZL, F BASEL, SWITZERLAND.

ALKYL AND ARALKYL RESORCINOL' CARBOXYLIC ACIDS.

Ho Drawing.

It is a known fact that among the 4, C- alkyland 4, C-aryl-alkyl derivatives of 1.3- dihydroxybenzene there are products which possess strong germicidal properties. The terms C-alkyl and C-aryl-alkyl indicate that the alkyl and the aryl-alkyl group are at tarhed to a carbon atom of 1.3-dihydroxybenzene. An attempt to render these products useful in therapy was unsuccessful, because on the one hand they irritate the mucous membrane and possess an exceedingly disagreeable taste, whereas on the other hand infections of the urogenital system are but slightly influen'cedby their administration, even if it extends over a long period. The reason for this is that these derivatives, on their passage through the human body, become wholly paired. Only with toxic dosages the unpaired bodies partly appear in the-urine.

It has now been found that the carboxylic acids corresponding with the resorcine derivatives just mentioned not only possess strong disinfecting properties even .in neutral'solution, but that they'pass unchanged through the human body. Moreover, the irritating action of the starting materials is no longer present. It is known that when phenol is converted into salicylic acid the starting materials almost entirely lose their germicidal properties. Sodiumsalicylate is only a very weak disinfectant; thus for instance a solution of sodiumsalicylate is unable to destroystaphylococci within three hours, whereas concentrated solutions of 0.1% of 4, p.phenyl-ethyl-1.3-dihydroxybenzene-G-carboxvlate of sodium are sufficient for destroying them within an hour.

The manufacture of the carboxylic acids of the 4, C-alkyland 4, C-aryl-alkyl 'derivatives of 1.3-dihydroxybenzene consists in treating the starting materials in. presence of alkali with rarbondioxide.

The carboxylic acids thus obtained are crystallized compounds which dissolve diflicultly in cold water, more easily in organic solvents. They are to be used as products for internal disinfection.

- Example 1. parts of 4, ,B-phenyl-ethyl-1.3-dihydroxybenzene. are heated with 200 parts of water and v'parts of sodium Iii-carbonate during 6 hours to 140 C. under pressure. After cooling unchanged 4, ,B-phcnyl-ethyl- 1.3-dihydroxybenzene is separated by filter- Applicatlon tiled June 1, 1927, Serial No. 195,868, and in Germany June 4, 19 26. v

' 1,697,33 PATENTOF-FICE.

ing and from the solution the carboxylic acld thus obtalned is precipitated with mineral acid. The acid, which immediately crystallizes, 1s re-crystallized from plenty of Water to which is added some coal, and is then obtained in colourless needles, which,

on being quickly heated, melt at about 208 (1', decomposition setting in at the same W1th ferric chloride the acid shows time. a deep blue colouring.

Example 2.

11 parts of metallic sodium are dissolved v in parts of absolute alcohol; to this solu- 13 1011 are added in an air-tight container IUD-120 C. After cooling 60 parts of concentrated hydrochloric acid are added and j the mixture stirred with 300 parts of benzol. The benzol is then removed and separated from the carboxylic acid by stirring with a solution of bi-carbonate, from which the free acid is obtained by acidifying.

Example 5.

70 parts of 4, ,B-p-brom-phenyl-ethyl-1.3-- d'ihydroxybenzene, obtained through jcondensation of" p-brom-benzyl-c anide with resorcine, saponifying the prom-benzylresorcyl-ketimide to p-brom-benzyl-resorcylketon and reducing according to-Clemmensen, its melting 'point bein 142 C., are dissolved in a solution of 5.5 parts of sodium and 150 parts of absolute alcohol. .The alcohol is then distilled off in a hydrogen current under reduced pressure and the remaining product heated during 5 hours with" carbon-dioxide to C. After dissolving in water carbonic acid is passed inauntil the phenolphtaleine reaction has disappeared, y

the unchanged 4, B-p-brom-phenyl-ethyl- 1.3-dihydroxybenzene is extracted with ether and the carbo-xylic acidrjprecipi'tated with mineral acid. It can be decolorated inether with charcoal and recrystallized from benzol. If the isomeric acids are to be separated, the reaction product is dissolved in a solution of soda, the crystallizing, diflicultly soluble sodium salt of -4, flap-bromhenyl ethyl-1.3-dihydroxybenzene oxylic acid filtered off and the r carboxylic acid (melting point 204 0., ferric reaction in alcohol violet) precipitated from thel e. The sodium salt'is converted into the e-2v-carboxylic acid in the usual manner (melting point 181 0., ferric reaction blue). 1 I

Ewwmple 4'.

21 parts of 4-heptyl-1.3 dihydroxybenzene are :dissolved' in a solution of 2.3 parts of sodium and 30 parts. of absolute alcohol. The alcohol is evaporated in a h rogen current under reduced pressure an 7 the remain ing product heated'with carbon-dioxide during 8 hours to about 90 C. After dissolvalcohol in a hydrogen current; the alcohol is then evaporated in vacuo, the residue after cooling slowly heated with carbon-dioxide brom Q phenyl-ethyl-lB-dihydrdxybenzne-G- ing in waterv and neutralizing with carbonic zene are dissolved in 200 parts of absolute V parts of sodium and 125 parts of absolute to 120-130 G. and left at this temperature for 4 hours. The further treatment con- S1StS,'8S in the case of 4, ,B-p-brom-phenylethyl-1.3-dihydroxybenzene-carboxylicacid, ui'introducing carbonic acid into the aqueous solution until the phenolphtaleine reaction has disappeared and separating the un changed starting material. The product thus obtained after acidifying is. de-

colorated in a solution 3 of ether and recrystallized from benzol. The acid crystallizes in white needles melting at 160 C. and

shows with ferric chloride a blue colouring.

gehe

y acid.

I claim: 1. As new products for internal disinfection, carboxlic acids of the C-alkyl and rincipal quantity consists of the 4- zene. v i

2. As new article of manufacture 4,1?-

phen leth l-' 1.3 dihydroxybenzene-B-cai boxy ic aci the new product consisting of colourless needles which, on bein heated -1.3 dihydroxybenzene 2 carboxylic C-aryl-alkyl derivatives of dihydroxybenquickl melt at about 208 (3., dissolving diificu tly in cold water, more easily in or anic solvents and showing with ferric chloride a deep blue colouring.

3. As a new article of manufacture the roduct phenyl-ethyl-dihydroxybenzene-caroxylic acid. A

In witness whereof I have hereunto set my hand.

HANS STENZL. 

